Game racket construction and method of fabricating the same



April 12, 1960 G. A. ALLWARD GAME RACKET CONSTRUCTION AND METHOD OF FABRICATING THE SAME Original Filed Dec. 9. 1953 2 Sheets-Sheet l Ill!) IIIIIX INVENTOR GUFGIEfi-FALWI/PO,

ATTORNEYS April 1960 G. A. ALLWARD 2,932,085

GAME RACKET CONSTRUCTION AND METHOD OF FABRICATING THE SAME Original Filed Dec. 9, 1955 2 Sheet-Sheet 2 I N VENTOR azzusffl flZLWRa,

BY Mw ATTORNEY- United States Patent GAME RACKET CONSTRUCTION AND METHOD OF FABRICATING THE SAME George A. Allward, Lacombe, La.

Original application December 9, 1953, Serial No. 397,093, now Patent No. 2,742,289, dated April 17, 1956. Divided and this application April 2, 1956, Serial No. 575,387

6 Claims. (Cl. 29-526) This invention relates to game racket structures and aims to provide an improved racket frame construction and an improved method of production thereof, particularly but not exclusively adapted for the production of a light, strong, resilient, warp-proof badminton racket.

The present application is in part a division and in part a continuation of my copending application Ser. No. 397,093, filed Dec. 9, 1953, now Patent No. 2,742,289, issued April 17, 1956, and has been filed as a result of a requirement for restriction made in said copending application under the authority of Title 35, United States Code, Section 121, to include claims to the novel method of construction therein disclosed and to illustrate specific structural modifications herein set forth. I

The invention resides in the novel features of construction and in the novel steps of the method hereinafter described and more particularly pointed out in the appended claims.

In the accompanying drawings of illustrative embodiments of the invention 1 Fig. 1 is a front elevation of one form of racket producedby the method of the present invention. Fig. 2 is-a side elevation thereof.

2,932,085 Patented Apr. 12, 196i) V 2 outer walls lying on the arc of a circle of radius r except for slight rounding of the four parallel external edges of the extruded strip. Similar proportions, designed to present the inner surface of the base web approximately at the neutral plane and to present a smooth rounded exterior, may be employed on a somewhat larger scale for tennis racket construction and the like. Summarizing these features of the cross section without reference to specific dimensions, it will be seen that the flat web has two flanges extending from it in the same direc* tion, and defining a rectangular groove therewith of a width approxiamtely one-third the overall width of the channel, the two flanges being rounded from the base of the web to the open edge of the rectangular groove; Also, that in the preferred embodiment the groove has a depth about twice the thickness of the web adjacent to it, the flange being rounded'on arcs having radii 8p:

Fig. 3 is a cross section through the head of the frame taken on the line 3--3, Fig. 1, looking in the direction of the arrows. s

Fig. 4 is a cross section through the shaft of the racket frame taken on the line 4-4, Fig. 1, looking in the dire'ction of the arrows.

Figs. 5, 6 and 7 are diagrams illustrative of the preferred method of manufacture. 1 v

Figs. 8, 9 and 10 are a longitudinal cross section, a plan view and a transverse cross section of a modified construction of channel lining arrangement.

Figs. 11 to 13 are a front elevation and sectional details of another form of racquet produced by the method of the invention and including certain novel structural features, and a Fig. 14 is a detail in perspective of another feature.

"Referring to Figs. 1-4, the racket frame of the present invention is formed from a single, continuous, solid, extruded channel 10 of light metal, preferably aluminum 'oran aluminum alloy. For a standardsized badminton racket the extruded channel or bar 10 may have a length of about 4% feet. This channel, in accordance with this invention has a special cross section, best shown in Figs. 3 and 4. In this cross section the neutral plane of bending lies substantially at the level of the inner bottom 11 of the channel groove, as indicated by the center lines 12-12 in Figs. 3 and 4. Thus when the channel is bent, as shown in Fig. 1, the'region of the bottom wall 11 undergoes substantially no elongation of foreshortening. As indicated in Fig. 3, for the standard badminton racket, the preferred dimensions of the channel strip are: overall width w about inch, overall depth d about inch, width of channel or groove g about $4; inch, thickness of base web I about ,5 inch,

the flanges f having straight parallel inner walls and proximatelyequal to half the overall width of the web. As .also shown in Fig. 3, in the preferred embodiment the arcs are swung about the median line of the flat side of the web as a center, and the channel has its neutral plane 1212 approximately at the level of the inside bottom of thegroove.

Still referring to the standard size badminton racket example, the central 27% inches of the four-and-one-half foot channel has adhesively secured therein a liner strip 13, preferably of soft leather about $4 of aninch thick, and the central 26% inches of the so lined channel is then perforated through the channel web and strip with holes P1 etc., properly spaced to provide for stringing of the racket. In the embodiment shown 68 stringing perforations are employed, the holes Pl'and P68 being placed approximately centrally .of the throat bends,as shown in Fig. 1, which throat bends are effected with an external radius of about'li inch, as hereinafter more fully described. Each of the perforations P1P68, at its inner. end viewed in Fig. 1 is countersunk slightly, the countersink in the case. of drilled perforation P17 being indicated at 17a in Fig. 3. Still referring to the illustrative embodiment of a standard badminton racket,

the perforations P34 and P35 at the tip of the racket head are spaced about di inch respectively from the center line of the racket, and the curvature at the throat bends P1-P68 also spaces the holes P1 and P68 about %vinch apart. Thus the spacing of the holes in each quadrant of the racket may be a duplicate of that in each other quadrant when a symmetrical head is employed, as in a standard badminton racket, that in the illustrative embodiment having seventeen holes to a quadrant preferably being as follows, measuring the distances P1--P2, etc. up to P1--P17, with P17 spaced about of an inch from P18: 7 inch, plus, l 1%, 2% %2, %6; 732, %2, %6. %2, /8 u 2 52, /iei As will be observed from the foregoing dimensions the soft liner strip extends approximately a half inch beyond the ends of the row of stringing holes, P1 to P68 in the illustrative embodiment, and thus extends inside the channel around the throat bends when the frame is shaped.

As will be apparent from Fig. 2, the frame is also provided, .when shaped, with a plurality of rivets R1--R5 set into the reentrant portions of the handle forming parts of the channels. The channels, before bending, are preferably formed with holes to receive at least one of these rivets, preferably holes for the rivet R2, which may lie about 2% inches from the first and last stringing holes P1 and P68. respectively. The holes for the rivets'Rl and R3 to R6 may be preformed or formed after the bending of the frame, as desired. 1

, The channel strip having been supplied with the liner, n e n ,pe forat as e n forme and countersunk, the frame blank is. ready. for bending. This bending operation is facilitated by the particular cross section of the channel, and the sequence of bending steps now to be described is particularlyadvantageous.

Referring to Fig. 5, in the first step of bending the lined straight frame blank has its handle forming end portions bent at right angles over a curved surface of a radius of approximately one quarter inch, with the bend positioned relative to the 1st and last stringing openings P1, P68, as above described, as illustrated in diagrammatic form.

7 During this sharp bending a slight flattening and inward flow of the tips of the flanges f occurs in eifect narrowing the mouth of the channel groove g and aiding in preventing the ends of the liner 13 from curling out of the groove if their adhesive securement should ultimately be come detached.

When the two end sections of the channel have been bent at right angles to the central section thereof, as indicated in Fig. 5, the central section is sprung backwardly as in Fig. 6 either with or without the aid of a mandrel and this springing is continued until the throat portions and handle portions are brought into contact with each other as shown in solid lines in Fig. 7. The handle members are then secured together in any suitable manner. When this securement is effected by riveting, at least two rivets, as R2 and R1, and preferably all of rivets R1-.-R5 are then inserted. Following the securement of the handle members together the frame is flattened to an oval shape as shown in dotted lines in Fig. 7 by pressure on the sides of the head in the regions hh. In general all stringing and rivet holes are pre-drilled or punched, and for, a standard badminton racket the ovalizing is conducted to produce an oval having 7%" by 9%" outside dimensions as illustrated in Fig. l, i.e. a major to minor axis ratio of about 39 to 31.

Due to the special shape of the channel member the bending of the extruded section does not materially alter the linear dimensions of the bottom face 11 of the groove 3 or tend to stretch the liner out of hole-to-hole alignment with the perforations P1-P68, and because of this advantage stringing of the formed racket is facilitated and separation of the liner from the channel member is avoided. Furthermore, as the liner turns the corners at the sharp throat bends under compression, and is seated in the channel at an area where its flanges are bent inwardly somewhat over the liner, all tendency of the liner to loosen and creep during the forming of the racket head is avoided. Following the springing of the head into the shape shown in solid lines in Fig. 7 the handle member '15 that may have a cylindrically drilled bore, is slipped over the ends of the shaft portions, that define a cylindrical cross section except for their grooves, and secured thereto, as by one or more rivets R6 passing therethrough in the form shown. The hole to receive the rivet R6 is preferably drilled clear through the handle 15 and the facing channel members after the latter have been driven tightly into the handle 15.-

In the form of Figs. 1-4, above described, the stringing holes are pre-drilled or punched and countersunk, and a liner preferably of leather is used, to protect against string cutting. In the modified form of Figs. 8-10, the leather strip 13 (Figs. 2 and 3) is replaced by a molded plastrc strip (113 having stringing sleeves b13 integral therewith and disposed to provide the proper string spacing for the shape of the racket head as above exemplified in connection with the stringing holes Pl-P68. The frame a is provided with enlarged stringing sleeve receivmg perforations or holes aP, preferably formed by a gang punch, and the sleeves b13 preferably terminate flush with the inner surface of the frame a10, as shown. By the liner molding and gang punching procedure, the assembly of the parts is expedited, and thesleeve lining of the stringing apertures affords complete protection against 4 string cutting. As before, the ends of the liner at and beyond the end holes (P1 and P68 in Fig. 1) are placed under compression by the throat bends and thus held against lifting.

In the form of Figs. 11-13, the liner 13 or 1213 is omitted, and in lieu thereof the perforations bP are chamfered or countersunk both at the fiat back ends bPa, and at the channel ends bPb thereof, to protect the strings from cutting.

Also this form includes a weight adjusting and decocating means, shown in the form of a plastic sleeve S slipped over the handle-forming parts of the channel between the head and the handle grip a15 of the racket. By applying a sleeve S of a known weight, in the location shown, the weight of the racket can be adjusted within limits without materially altering the balance and center of percussion of the racket. The weight of the sleeve may be selected for this purpose and may be augmented to a degree by the application of one or more bindings B, B1, :18 and bB, described below. The sleeve S, in the form shown, is tubular and preferably loose fitting to facilitate its placement and is further weighted, decorated, and reinforced by ornamental Celluloid or plastic tape bindings B, B1, that may be fluted to give the appearance of wrapping, and that may be wrapped around the sleeve S and secured thereabout or thereto by adhesive or solvent, either before or after the sleeve S is slipped into place on the handle. If desired, when the sleeve S is loose fitting, and the bindings B are applied after its placement, such bindings may compress it to the channel members as shown. In this form also a grip G is applied to the handle a15, shown as a spiral leather wrapping with a tapered leather binding tB tacked on at its butt end and a plastic binding aB like that applied to the sleeve S, at its other end. Further bindings may be applied to the head forming portions of the channel member, as at bB, for ornamentation when desired, whether the sleeve S is employed or not, and the binding B, when sleeve S is not employed, may conceal the openings into the handle grip member that are left when it is cylindrically bored and slipped over and attached to the grooved cylindrical shaft provided by the cooperating straight end portions of the channel member, as shown in Fig. 14.

The forms of Figs. 8-10 and Figs. 1l-13 are preferably constructed by the same method described in connection with Figs. 1-4, with the advantages noted except that the advantage relating to securement of the liner is excluded when manufacturing the unlined form illustrated in Figs. 11-13.

While there have been described herein what are at present considered preferred embodiments of the invention, it will be obvious to those skilled in the art that any modifications and changes may be made therein without departing from the essence of the invention. It is therefore to be understood that the exemplary embodiments are illustrative and not restrictive of the invention, the scope of which is defined in the appended claims, and that all modifications that come within the meaning and range of equivalency of the claims are included therein.

I claim:

1. The method of forming a racket frame member consisting of a head portion and a handle portion that comprises cutting a length of flexible metal channel having a Web portion with two flanges extending in the same direction therefrom and defining a groove, and of such eross-section-that the natural bending plane of said channel passes through said web portion, forming a set of stringing perforations through said Web in the central or intermediate portion of said length of channel, bending the end portions of said length of channel substantially perpendicular to said central portion thereof and toward the groove therein, then bending said central portion of said length of channel into circular form to produce the racket head in such a manner that the neutral bending plane is in the bottom or web portion thereof so as to prevent substantial distortion of the preformed stringing perforations in said web portion and until said bent end portions are moved into abutting relationships, and thereafter securing the abutting bent end portions of said length of channel to produce the racket handle.

2. The method of claim 1, the securing of the abutting end portions as aforesaid being effected by riveting said abutting end portions together through the web portions thereof with the beaded ends of the rivets lying in the grooves thereof.

3. The method of claim 1, further comprising the step of applyingpressure to the sides of said head portion sufiicient to permanently deform said head into an oval shape.

4. The method of claim 1, further comprising the step of forming rivet holes through the web portions of said end portions in symmetrically spaced relation to the end perforations of said stringing set before bending said length of channel as aforesaid.

5. The method of claim 1, in which the channel from which the length is cut as aforesaid is formed of solid extrudedaliihrinum, with its web flat, with its groove approximately one-third the overall width of the channel, and with the external faces of its flanges arcuately shaped so that when said end portions are secured as aforesaid, the abutting end portions cooperate to define a handle of reentrantly grooved circular cross-section.

6. The method of claim 5, further comprising the steps of forming a single cylindrical socket in a handle grip with said socket conforming in diameter to the diameter of said reentrantly grooved circular cross-section, and socketing said cylindrical socket over the free ends of said end portions and securing the same thereon.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES The Iron Age (vol. 172; issue 8), Aug. 20, 1953 (pages 134 and 135 relied on). 

